Application of k 0-based internal mono-standard PGNAA for compositional characterization of cement samples

The k ₀-based internal mono-standard prompt gamma-ray neutron activation analysis (IM-PGNAA) method was used for compositional analysis of a cement standard provided by the International Atomic Energy Agency as a part of inter-laboratory comparison exercise. The PGNAA was also applied to a local cement sample for comparison purpose. The concentration ratios of elements with respect Ca were determined using the internal mono-standard method. The concentration ratios were then converted to the absolute concentrations by determining concentration of Ca in the cement using relative method. Concentrations of 11 elements were determined in both sample and standard of cement. The results of cement standard are found to be in good agreement with the certified values. The uncertainties on the elemental concentrations were in the range of 5–10 %.     

Curvature inequalities for operators in the Cowen-Douglas class and localization of the Wallach set

For any bounded domain Ω in ?^m, let B₁(Ω) denote the Cowen-Douglas class of commuting m-tuples of bounded linear operators. For an m-tuple T in the Cowen-Douglas class B₁(Ω), let N_T (w) denote the restriction of T to the subspace \(\cap^m_{i,j=1}{\rm{ker}}(T_i-w_iI)(T_j-w_jI)\). This commuting m-tuple N_T (w) of m + 1 dimensional operators induces a homomorphism \({\rho _{{N_T}\left( w \right)}}\) of the polynomial ring P[z₁, · · ·, z_m], namely, \({\rho _{{N_T}\left( w \right)}}\) (p) = p(N_T (w)), p ∈ P[z₁, · · ·, z_m]. We study the contractivity and complete contractivity of the homomorphism \({\rho _{{N_T}\left( w \right)}}\). Starting from the homomorphism \({\rho _{{N_T}\left( w \right)}}\), we construct a natural class of homomorphisms \(\rho_{N^{(\lambda)}(w)}\), λ > 0, and relate the properties of \(\rho_{N^{(\lambda)}(w)}\) to those of \({\rho _{{N_T}\left( w \right)}}\). Explicit examples arising from the multiplication operators on the Bergman space of Ω are investigated in detail. Finally, it is shown that contractive properties of \({\rho _{{N_T}\left( w \right)}}\) are equivalent to an inequality for the curvature of the Cowen-Douglas bundle E_T. However, we construct examples to show that the contractivity of the homomorphism ρ_T does not follow, even if \({\rho _{{N_T}\left( w \right)}}\) is contractive for all w in Ω.     

On the convergence of a second order approximation of conservation laws with discontinuous flux

A second order scheme is constructed for the scalar conservation laws with flux function allowed to be discontinuous in the space variable. The corresponding numerical solutionis shown to converge to the (A,B) entropysolution. Numerical results are presented to validate the convergence analysis. In addition, it is inferred that these numerical solutions are comparable with those obtained using the standard minmod limiter.     

Brownian dynamics of rigid body by fluctuating hydrodynamic equations

In this work, Brownian dynamics of rigid body in an incompressible fluid with fluctuating hydrodynamic equations is presented. To demonstrate the Brownian motion of rigid body, fluctuating hydrodynamic equations have been coupled with equations of motion of rigid body. Thermal fluctuation is included in the fluid equations via random stress terms unlike the random terms in the conventional Brownian dynamics type approach. Calculation of random stress terms in the fluid is easier in comparison to the random terms in the particle motion. Direct numerical simulation for the Brownian motion of rigid body with a meshfree framework is analysed. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Equivalence of the Generalized Vertical Block Linear Complementarity Problems and Linear Complementarity Problems

In this paper, generalization of a vertical block linear complementarity problem associated with two different types of matrices, one of which is a square matrix and the other is a vertical block matrix, is proposed. The necessary and sufficient conditions for the existence of the solution of the generalized vertical block linear complementarity problem is derived and the relationship between the solution set of the generalized vertical block linear complementarity problem and the linear complementarity problem is established. It is proved that the generalized vertical block linear complementarity problem has the P-property if and only if the vertical block linear complementarity problem has the P-property.     

Free volume and microstructural investigation of poly(ethylene terephthalate)-g-acrylic acid (PET-g-AA) copolymer films

Acrylic acid (AA) was grafted onto PET films by preirradiation method using a ⁶⁰Co γ-radiation source. Microstructural investigation of the PET-g-AA copolymers has been carried out by wide angle X-ray diffraction (WAXD), dynamic mechanical analysis (DMA) and positron annihilation lifetime spectroscopy (PALS) techniques. The WAXD results showed only marginal variation in the crystallinity of the graft copolymers. Dynamic mechanical analysis showed an increase in the temperature of the α-relaxation and the tan δ value of subroom temperature secondary relaxations. From the PALS results, a complex variation of the free volume parameters, i.e. the o-positronium lifetime (τ₃), its intensity (I₃), fractional free volume (f_v) and the intermediate lifetime component was observed for the graft copolymers. Multiple phenomena of the effect of secondary relaxations, additive behavior of the individual polymer free volume parameters and effects from interfacial defects have been invoked to understand the fluctuational nature of the free volume properties in the graft copolymers.     

Angular momentum transfer in incomplete fusion

Isomeric cross-section ratios of evaporation residues formed in¹²C+⁹³Nb and¹⁶O+⁸⁹Y reactions were measured by recoil catcher technique followed by off-line γ-ray spectrometry in the beam energy range of 55.7–77.5 MeV for¹²C and 68–81 MeV for¹⁶O. The isomeric cross-section ratios were resolved into that for complete and incomplete fusion reactions. The angular momentum of the intermediate nucleus formed in incomplete fusion was deduced from the isomeric cross-section ratio by considering the statistical deexcitation of the incompletely fused composite nucleus. The data show that incomplete fusion is associated with angular momenta slightly smaller than critical angular momentum for complete fusion, indicating the deeper interpenetration of projectile and target nuclei than that in peripheral collisions.     

Angular distributions and cross-sections of projectile-like fragments in the 19F + 159Tb reaction

The angular distribution of projectile-like fragments (PLFs) in the ¹⁹F + ¹⁵⁹Tb reaction have been measured at beam energy equal to 98MeV. Angular distributions of PLFs showed a systematic change with increasing mass transfer, starting from the peaking at grazing angle for heavier PLFs to very forward peaked angular distributions for lighter PLFs. Cross-sections of the different PLFs were obtained by integrating their centre-of-mass angular distributions. The PLF cross-sections have been compared with the incomplete fusion cross-sections obtained from the earlier measurement of the evaporation residue cross-section. Reduced cross-sections for lighter PLFs were observed to be higher compared to those observed in ¹⁹F + ⁶⁶Zn reaction at similar values of E _cm/V _b. Also, elastic scattering measurements were carried out to get information about the grazing angle and total reaction cross-section.     

Photo-induced DNA cleavage activity and remarkable photocytotoxicity of lanthanide(III) complexes of a polypyridyl ligand

Lanthanide(III) complexes [Ln(pyphen)(acac)(2)(NO(3))] (1, 2), [Ln(pydppz)(acac)(2)(NO(3))] (3, 4) and [La(pydppz)(anacac)(2)(NO(3))] (5), where Ln is La(III) (in 1, 3, 5) and Gd(III) (in 2, 4), pyphen is 6-(2-pyridyl)-1,10-phenanthroline, pydppz is 6-(2-pyridyl)-dipyrido[3,2-a:2',3'-c]phenazine, anacac is anthracenylacetylacetonate and acac is acetylacetonate, were prepared, characterized and their DNA photocleavage activity and photocytotoxicity studied. The crystal structure of complex 2 displays a GdO(6)N(3) coordination. The pydppz complexes 3-5 show an electronic spectral band at ~390 nm in DMF. The La(III) complexes are diamagnetic, while the Gd(III) complexes are paramagnetic with seven unpaired electrons. The molar conductivity data suggest 1 : 1 electrolytic nature of the complexes in aqueous DMF. They are avid binders to calf thymus DNA giving K(b) in the range of 5.4 × 10(4)-1.2 × 10(6) M(-1). Complexes 3-5 efficiently cleave supercoiled DNA to its nicked circular form in UV-A light of 365 nm via formation of singlet oxygen ((1)O(2)) and hydroxyl radical (HO˙) species. Complexes 3-5 also exhibit significant photocytotoxic effect in HeLa cancer cells giving respective IC(50) value of 0.16(±0.01), 0.15(±0.01) and 0.26±(0.02) μM in UV-A light of 365 nm, while they are less toxic in dark with an IC(50) value of >3 μM. The presence of an additional pyridyl group makes the pydppz complexes more photocytotoxic than their dppz analogues. FACS analysis of the HeLa cells treated with complex 4 shows apoptosis as the major pathway of cell death. Nuclear localization of complex 5 having an anthracenyl moiety as a fluorophore is evidenced from the confocal microscopic studies.     

Ring-closing metathesis in the synthesis of fused sultones

Synthesis of seven-membered sultones fused with different carbo- and heterocycles have been developed using ring closing metathesis as the key operation. The required substrates have been easily synthesized from their commercially available corresponding phenols.